Prior to the euro, the topics of constitutional law and monetary policy rarely overlapped. Money was regulated, on the national level, through the ordinary legislative procedures. For European monetary union, the use of constitutional law was nevertheless attractive because it meant that the MS would be in control of the negotiation process, because it enabled a very independent central bank and because it kept the MS in control over the future of the euro. The lack of trust among MS to share a currency was overcome by an abundant trust in law. As the euro was negotiated as a constitutional currency, this created specific opportunities and obstacles for the different parts of the EMU. Once the euro finally came into existence, the constitutional framework of the euro proved remarkably stable for the first decade and a half. After the excitement of Maastricht, monetary policy very quickly became boring again, in no small part due to constitutional law. Unfortunately, EMU primary law was quite successful. During the euro-crisis, EMU primary law shaped the responses to the crisis by placing fewer obstacles on some routes to change than on others. As the crisis developed, some conflicts became the topic of much legal debate and even judicial decisions, whilst other parts of euro-crisis law met with few objections, despite some legally problematic aspects. The possibilities for further reform of the Eurozone without treaty change are then largely the result of the process of reform until now.

Version: Chapter 3 ‘The constitutional Euro' of the PhD thesis draws upon an earlier version published as a working paper 'The variable geometry of the eurocrisis: a look at the non-euro area Member States' (2015), 2015/33 EUI Working Paper Law.; Chapter 1 ‘Monetary policy and constitutional law before the euro' of the PhD thesis draws upon an earlier version published as a contribution 'Maastricht revisited: economic constitutionalism the ECB and the Bundesbank' (2014) in the book ‘The constitutionalization of European budgetary constraints’; The conclusion of the PhD thesis draws upon an earlier version published as an article 'EU law for a new generation?' (2016) in the journal ‘International journal of constitutional law’